Conventionally, fluorescent lamps and light bulbs have been widely used as illumination lamps. Recently, in view of power consumption and service life, various light emitting devices using light emitting diodes (LEDs) are being developed as substitutes for the conventional lamps.
A related art light emitting device provides white light by a combination of a semiconductor light emitting device that emits near ultraviolet rays, a blue phosphor, and a yellow phosphor. For example, a light emitting device has a first light emitter that emits light of 350 nm to 415 nm and a second light emitter that emits visible light when irradiated with the light from the first light emitter, the second light emitter having a chemical composition represented by a general formula of EuaCabM5-a-b(PO4)cXd, where M is a metal element other than Eu and Ca, and X is a monovalent anionic group other than PO4 (see, e.g., JP 2005-060468 A).
Light emitting devices, such as LEDs, are also being used in recent vehicle headlamps. When using LEDs in a headlamp, it is advantageous to reduce the number of LEDs in terms of reducing cost, in which case the output per one LED increases.
However, in a light emitting device using a combination of a high output LED and a phosphor, the high output LED may deteriorate the phosphor and cause reduction in light emission intensity of the light emitting device.